How to show multiple tabs in the same interface ?

I dont know if I can ask for this question here but I remember having an option to show two or more tabs in the same interface, I remember doing this by pressing CTRL + selecting tabs and then right click and then there there was an option to merge the selected tabs in the same interface. I tried recently to do this and can not find any proper option to do so, can anybody advice what option can I use now in order to achieve this ? I just don`t want to install extra plugins if possible. Thanks.